Fibers of glass and other thermoplastic materials are useful in a variety of applications including acoustical or thermal insulation materials. Common prior art methods for producing glass fiber insulation products involve producing glass fibers from a rotary process. A single glass composition or multiple glass compositions are melted and forced through orifices in the outer peripheral wall of a centrifuge, known as a centrifugal spinner, to produce the fibers. One commonly used spinner is generally cup shaped with a bottom wall with a central hole, a top opening and an outer peripheral wall which curves upward from the bottom wall, forming the top opening. The lower end of a drive shaft, used to rotate the spinner, extends down through the top opening and is fixed to the center of the bottom wall with a quill. The central hole of the bottom wall is simply press-fit onto the outside diameter of the quill, and the quill is mounted to the lower end of the drive shaft.
The spinner becomes very hot during the fiber manufacturing process. Because of the high temperatures reached, the spinner walls are necessarily made from a high temperature resistant material, typically a high temperature metal alloy. Even so, at such high temperatures, the spinner exhibits a tendency to creep and sag downward as the spinner rotates. This deformation of the spinner can introduce process variables that adversely impact fiber production.
In addition, because it is simply press-fit on to the quill, the spinner has a tendency to loosen around the quill over time, due to thermal expansion, rotational stresses and creep to which the spinner and quill are subjected. As the fit loosens, the spinner moves off-center, resulting in a serious problem of excessive vibration and warping of the spinner. This problem becomes more pronounced as the size of the spinner, and thus the diameter of the central hole, increases.
Accordingly, there is a need for an improved spinner that is less likely to exhibit temperature induced deformation that introduces undesirable process variables during the fiber manufacturing process.